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| author | Anthony PERARD <anthony.perard@citrix.com> | 2014-10-29 06:49:55 +0000 |
|---|---|---|
| committer | jljusten <jljusten@Edk2> | 2014-10-29 06:49:55 +0000 |
| commit | bba9d16231fe9f7d67e0530e720530d91a88ad73 (patch) | |
| tree | a5ea457e342d026ecac745eb64b55afe63422b32 /OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h | |
| parent | 12a16f2d1c610942a3420c86e7a3c6bcc7a6eedf (diff) | |
| download | edk2-platforms-bba9d16231fe9f7d67e0530e720530d91a88ad73.tar.xz | |
OvmfPkg/XenBusDxe: Add InterlockedCompareExchange16.
This patch is inspired by InterlockedCompareExchange32 from the
BaseSynchronizationLib.
The function will be used in the "OvmfPkg/XenBusDxe: Add Grant Table
functions" patch.
Change in V3:
- Implement both .S and .asm, to get rid of GCC specific asm.
- Implement 32bit part of the assembly
Change in V2:
- Add intel compilation code
MSFT code is not compied over because I don't know how it works.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16263 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h')
| -rw-r--r-- | OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h new file mode 100644 index 0000000000..fd3f15b1c8 --- /dev/null +++ b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h @@ -0,0 +1,38 @@ +/**
+ Assembly implementation of InterlockedCompareExchange16.
+
+ Look at the documentation of InterlockedCompareExchange16.
+**/
+UINT16
+EFIAPI
+InternalSyncCompareExchange16 (
+ IN volatile UINT16 *Value,
+ IN UINT16 CompareValue,
+ IN UINT16 ExchangeValue
+ );
+
+/**
+ Performs an atomic compare exchange operation on a 16-bit unsigned integer.
+
+ Performs an atomic compare exchange operation on the 16-bit unsigned integer
+ specified by Value. If Value is equal to CompareValue, then Value is set to
+ ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
+ then Value is returned. The compare exchange operation must be performed using
+ MP safe mechanisms.
+
+ If Value is NULL, then ASSERT().
+
+ @param Value A pointer to the 16-bit value for the compare exchange
+ operation.
+ @param CompareValue 16-bit value used in compare operation.
+ @param ExchangeValue 16-bit value used in exchange operation.
+
+ @return The original *Value before exchange.
+**/
+UINT16
+EFIAPI
+InterlockedCompareExchange16 (
+ IN OUT UINT16 *Value,
+ IN UINT16 CompareValue,
+ IN UINT16 ExchangeValue
+ );
|